1. Field of the Invention
The invention relates in general to an optical disk drive, and more particularly to a temperature compensation method for laser power of an optical disk drive when temperature changes.
2. Description of the Related Art
Optical disk drive, which employs laser diode as the light source, must have stable laser power so as to emit a quality light beam to read, write, or erase data of the optical disc. Laser diode is very sensitive to temperature, and temperature change will change the wavelength of the light emitted by laser diode and make the laser power difficult to maintain stable, hence affecting the quality of reading/writing data by the optical disk drive.
Referring to FIG. 1, a laser power curve of a conventional optical disk drive is shown. In order to stabilize the laser power, the conventional optical disk drive will test the laser power generated by laser diode in the test area of an optical disc by use of different input voltages or input currents. Next, a linear-fitting laser power curve is obtained from several test points according to a curve fitting algorithm. Then, the laser power curve is used as a parameter for the optical disk drive to control the laser diode and emit a light beam with stable laser power, hence maintaining the quality of reading/writing data.
However, the laser power of the optical disk drive will largely change as the temperature of the optical disk drive changes, and the laser power curve disclosed above is merely applicable to the temperature measured when the optical disk drive is tested. As the temperature of the optical disk drive rises when the optical disc drive operates, the laser power is too high or the working environment is heated, the laser power generated by the laser diode will decay, hence affecting the quality of reading/writing data. Another convention optical disk drive has a temperature sensor which detects the temperature of the disk drive, and once the temperature change is over a predetermined value, the optical disk drive will perform new test of laser power to compensate temperature change. However, the implementation of new test not only spends extra time but also reduces the efficiency of the optical disk drive. Therefore, how to tackle with the many problems regarding temperature compensation method for laser power of optical disk drive has become an imminent issue to be resolved.